1. Field of Invention
The present invention relates to an electro-optical apparatus using a current-driven device that is driven by an applied current as a light-emitting device and to a method of driving the electro-optical apparatus.
2. Description of Related Art
Display apparatuses using liquid crystals have become increasingly used as thin displays in recent years. Displays of this type consume lower power and occupy less space, compared with cathode ray tube (CRT) displays. Hence, it is important to utilize the advantages of such displays to manufacture lower-power-consumption and more-compact displays.
Displays of this type include displays using current-driven light-emitting devices, instead of liquid crystal devices. Since current-driven light-emitting devices are self luminous devices, which emit light in response to a supplied current, unlike liquid crystal devices, they need no backlight and, therefore, they can accommodate the marketing demand for low power consumption. Furthermore, current-driven light-emitting devices have superior display performance including wider viewing angle and higher contrast ratio. Among such current-driven light-emitting devices, electroluminescent devices (EL devices) are especially appropriate for displays because large-area and high-resolution EL devices can be realized in full color.
Among EL devices, organic EL devices have drawn attention because of their high quantum efficiency.
FIG. 10(a) illustrates an example of a circuit (pixel circuit) for driving such an organic EL device. FIG. 10(b) is a timing chart showing the operation of the circuit in FIG. 10(a). Referring to FIG. 10(a), a pixel circuit 201 includes two transistors, that is, an n-type transistor T8 and a p-type transistor T9, a data-holding capacitor C, and an organic EL device 11. The transistor T9 is switched by a signal supplied through a gate line 12, and a data signal Vdata supplied through a data line 13 is held in the data-holding capacitor C as an electric charge. The electric charge held in the data-holding capacitor C causes the transistor T8 to be conductive and, thus, a current corresponding to the data signal Vdata is supplied to the organic EL device 11, which emits light. See, for example, PCT Publication No. WO98/36407.